The old axiom is that defense wins championships. That's true to some extent, but you have to score, too, and we will see plenty of points in the Western Conference finals. In a series pitting the high-flying Oklahoma City Thunder against the ultra-efficient San Antonio Spurs, we have a matchup featuring a pair of offenses that take very different routes to get to the same place.

The Spurs and Thunder were the two most efficient offenses in the league this past season. In fact, when you adjust for the fact that this post-lockout campaign resulted in a league-wide efficiency that was down by 2.6 points per 100 possessions, these were two of the 50-most efficient offenses of the 3-point era. San Antonio clocked in at 22nd on that scale by putting up points at a rate 6 percent better than the league average.

The overall efficiency of offenses in the playoffs has declined by another 2.5 points from the regular season, a typical trait of postseason basketball. However, the attacks of the Spurs and Thunder have gotten even better. Oklahoma City leads all teams in postseason points per possession, just ahead of the Spurs. If we convert those results to the same aforementioned scale, the Thunder has been 10.1 percent better than the typical playoff offense; the Spurs aren't far behind at 9.7 percent. If these teams had put up those numbers during the regular season, we'd be talking about the two most efficent attacks of the 3-point era.

So what happens when the irrestible force meets the irresistible force? Here are five things we've learned about San Antonio and Oklahoma City.

1. The Thunder has to be more disciplined on defense, Part I.
No matter how you slice it winning eight straight playoff games, as the Spurs have done, is impressive. But they haven't exactly been going against the league's elite defenses. The Los Angeles Clippers and Utah Jazz--San Antonio's first two postseason opponents--ranked 18th and 19th respectively on the defensive end. Oklahoma City was better, ranking ninth, but weren't elite, either. That's held true in the playoffs, where the Thunder ranks below the league average in point prevention.

How can a team with so much size, youth and athleticism be anything but dynamic on defense? Part of it is a question of emphasis. Oklahoma City was the fourth-best team in the league contesting shots, but they were in the bottom third when it came to cleaning up those misses off the defensive boards. The Thunder love to run on offense--and why wouldn't they?--but too often do so at the expense of abandoning the defensive glass too soon.

The Thunder was NBA's fourth-best team in points per shot off transition, but ranked just eighth in overall fastbreak points. They have to maximize their fastbreak opportunities by sealing off the defensive glass against a Spurs team that doesn't really emphasize offensive boards, and ranked right with the Thunder in the middle of the pack when it came to stopping transition.

2. The Thunder has to be more disciplined on defense, Part II.
Despite the elite athleticism of Kevin Durant, Russell Westbrook and James Harden and the fact that the Thunder has premier shot blockers Serge Ibaka and Kendrick Perkins at the back of their defense, Oklahoma City doesn't really pressure the ball all that well, ranking just 23rd at forcing turnovers. That's a schematical preference, of course, as Scott Brooks favors sound defensive rotation and shot-challenging over taking chances in the passing lanes.

Where that could bite the Thunder against San Antonio is on corner 3s. Only three teams allowed more looks from the corner than Oklahoma City, while the Spurs led the league from those spots. That's a staple of the Gregg Popovich system--a small forward who camps out in the corner while the Tony Parker, Manu Ginobili and Tim Duncan do their thing. The Thunder has to be disciplined with its help defense and must find the balance between aiding a beaten teammate and leaving the likes of Danny Green and Gary Neal wide open in the short corners.

3. The regular season doesn't tell us much about this matchup.
Often, regular-season matchups can tell us a lot about how a playoff series might unfold, but that isn't likely the case here. As my Basketball Prospectus colleague Kevin Pelton pointed out, the three games between these teams can only tell us so much. San Antonio won two of those, but Ginobili missed all three of the contests. Neither of San Antonio's key in-season acquisitions, Stephen Jackson and Boris Diaw, played against Oklahoma City. Derek Fisher wasn't around for the Thunder. The teams played just once after the All-Star break, a 114-105 San Antonio win at Oklahoma City on March 16 that came in the second game of a back-to-back for the Thunder. The Spurs lost their next game, and have gone 29-3 since then. These are different teams playing at different levels than at any time when they met in the regular season.

4. The Spurs will have to contain the Thunder's pick-and-roll.
As has been written many times, this is not the kind elite Spurs defensive team that has come to mark the Duncan-Popovich era. However, while the Spurs ranked just 11th overall on the defensive end, they've gotten steadily better as the season has progressed. San Antonio's per month ranking in defensive efficiency from January to April goes like this: 21st, 15th, ninth, fourth. In the postseason, San Antonio ranks fourth.

That said, the Thunder have a significant athletic advantage in the series and that shows up in a couple of areas. The Spurs ranked 22nd against isolations this season, and were dead last at defending the ballhandler on the pick-and-roll. If you can break down the San Antonio defense into its component parts and get it on the move, you can beat it, if you have the personnel to do so. No team presents a bigger challenge in this regard than the Thunder, which was the top team in the NBA in both of those areas of weakness in the Spurs' defensive wall. Simply put, San Antonio doesn't have anybody that can keep up with Westbrook or Durant in space.

5. The streak can't last forever. Can it?
San Antonio comes into the series on an 18-game winning streak. With each win, the flurry enters more rarified air. When you combine regular-season and postseason streaks, there have been just six of longer duration in NBA history. The Spurs have had two other streaks of 17 games or longer in franchise history. The first came in 1995-96, before Popovich manned the sidelines and Duncan the middle, and Bob Hill's Spurs rolled to 59 wins, only to lose in the Western Conference semifinals.

More telling was the streak in 2004 that, like this one, overlapped the regular season and the playoffs. San Antonio's 17th straight win came in the first two games of a second-round series against the Lakers. At that point, the then-defending champs seemed pretty invincible, having won all six of its playoff games, five of them by 10 points or more. They then lost four straight to L.A., which went on to lose in the NBA Finals.

Of course losing once is different than losing the four games it takes to lose a series but if there has been one theme we've been harping on in this postseason, it's that one game, or series, has nothing to do with the one before, or the one after. San Antonio has gone 8-0 against a pair of opponents they had soundly outmatched. However, the Thunder has lost only once, and OKC has a clear advantage in youth and athleticism. The Spurs may be functioning on all cylinders, but they start from scratch tonight in what should be a crazy, close and exciting series.